首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   7614篇
  免费   493篇
各国政治   369篇
工人农民   299篇
世界政治   499篇
外交国际关系   259篇
法律   5246篇
中国政治   40篇
政治理论   1356篇
综合类   39篇
  2020年   166篇
  2019年   173篇
  2018年   189篇
  2017年   224篇
  2016年   234篇
  2015年   207篇
  2014年   189篇
  2013年   815篇
  2012年   169篇
  2011年   184篇
  2010年   220篇
  2009年   233篇
  2008年   179篇
  2007年   178篇
  2006年   184篇
  2005年   172篇
  2004年   199篇
  2003年   171篇
  2002年   146篇
  2001年   319篇
  2000年   259篇
  1999年   235篇
  1998年   108篇
  1997年   74篇
  1996年   78篇
  1995年   84篇
  1994年   98篇
  1993年   98篇
  1992年   162篇
  1991年   168篇
  1990年   159篇
  1989年   160篇
  1988年   132篇
  1987年   138篇
  1986年   126篇
  1985年   137篇
  1984年   107篇
  1983年   122篇
  1982年   87篇
  1981年   79篇
  1980年   59篇
  1979年   113篇
  1978年   70篇
  1977年   60篇
  1976年   51篇
  1975年   51篇
  1974年   56篇
  1973年   55篇
  1972年   45篇
  1968年   40篇
排序方式: 共有8107条查询结果,搜索用时 0 毫秒
941.
942.
The method of choice to determine erythrocyte glutamate-pyruvic transaminase (GPT) including rare variants was starch gel electrophoresis. Methods using agarose as gel medium were not reported to our knowledge. We present an adapted method using the Tris/maleate buffer system and an agarose of low endosmosis. The common as well as rare variant types of GPT were quickly and reliably separated. In addition, a method for the consecutive determination of esterase D (ESD) and GPT on the same gel using the malic acid buffer system is described.  相似文献   
943.
944.
945.
946.
Congress plays a central role in national environmental policy formation but appears ill equipped to set policy priorities and devise integrative legislation. Fragmentation of authority among a multiplicity of committees and subcommittees, especially in the House, contributes to these problems. This pattern is evident in the evolution of Superfund, the national program to clean up abandoned hazardous waste sites. The prolonged process of reauthorization in the 1980s contributed to serious program delay and failed to resolve a number of fundamental questions concerning the national cleanup effort. Institutional reforms could contribute to a more effective congressional role in future environmental policy deliberations.  相似文献   
947.
Supravital electrical excitability of muscles   总被引:1,自引:0,他引:1  
A new method of postmortem electrical stimulation of muscles, measuring the force of the reaction against time, is presented. Preliminary investigations have yielded the following results: The maximum force of reaction in response to a definitive stimulation, measured by a sensitive force transducer, decreases in proportion to the post mortem interval. Using this method, the mechanical reactions of muscles by electrical stimulation can be demonstrated over a much longer postmortem period as these movements are visible. The duration of postmortem reaction of different muscles seems to be much more uniform than was previously assumed. Occasionally, reactions of the M. orbicularis oculi can be seen for the longest time. The basal muscular tonus changes relative to time. The time course of a single force reaction also changes relative to the postmortal interval: the reaction becomes slower. It has been theoretically established that measurement of influencing factors such as temperature and pH in the tested muscle will enable the time of death to be more precisely estimated.  相似文献   
948.
949.
A current Supreme Court case concerning lawyer advertising, In re R.M.J., is analyzed in the context of a discussion of the diverse state regulations governing lawyer advertising and solicitation. The article considers the regulations in terms of their constitutionality, their tendency to impede effective advertising, and the effect they have on the legal profession's provision of information to potential clients about the nature, availability, and cost of legal services. Analysis of the major commercial speech cases, from Virginia State Board of Pharmacy to Central Hudson, indicates that many state rules infringe on attorneys' First Amendment rights.  相似文献   
950.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号